This proposal will assess the quantitative capabilities of surface enhanced Raman scattering (SERS) detection of cocaine and marijuana metabolites in urine samples. Combining low-cost instrumentation and novel chemical sensing provides an innovative new approach for diagnosing illicit drug use. Current methods use a colorimetric indicator to screen specimens for more extensive quantitative analysis in dedicated laboratory facilities. Raman spectroscopy offers a low cost, chemical specific method with potential to determine the concentration of drug related metabolites in biological samples. Ultrasensitive analysis will be achieved using an online SERS flow detector developed in the laboratory of Dr. Z. Schultz at the University of Notre Dame. This flow detector will be evaluated in a Snowy Range Instruments (SnRI) Raman system to determine the necessary requirements for low-cost device that can identify and quantify the presence of drug metabolites comparable to the analysis currently performed in offsite laboratories. Our ultimate goal is a chemical specific, quantitative point-of-care diagnostic that could be produced for $5000. In this phase I project, the Schultz lab will demonstrate the quantitative capabilities of the SERS flow detector for the detection of cocaine and marijuana metabolites. SnRI engineers will incorporate the flow into a commercial Raman system and to determine which components are essential for incorporation in a low cost phase II prototype, appropriate for point-of-care use by non-technical experts. This collaborative research effort will result in new, low cost technology for accurate diagnosis of drug use.